Various lower olefinic stocks are available from petroleum sources, and many procedures are known for converting lower olefins to high olefins, or to higher molecular weight compounds with various functional groups. Among such procedures are catalytic dimerization procedures for converting propylene and butenes to heptenes and octenes respectively and such dimers can be catalitically hydroformylated to aldehydes, which can be reduced to alcohols. Lower olefins can be hydroformylated, using rhodium, cobalt, or other catalysts, to the corresponding aldehydes. Aldehydes in turn can be converted to higher aldehydes by the well known aldol reaction, such as that taught in U.S. Pat. No. 2,921,089 for converting n-vale aldehyde to 2-propyl-2-heptanol, and then hydrogenated to 2-propylheptanal and 2-propylheptanol. It is also known that various alcohols can be utilized to esterify phthalic acid to form useful plasticizers, e.g. 2-ethylhexanol, 2-propylheptyl alcohol, decyl alcohols, etc. as disclosed in the aforesaid U.S. Pat. No. 2,921,089. It is also known to conduct an aldol reaction of mixtures of normal and branched aldehydes under conditions which force cross aldol reaction of the branched aldehyde with the normal aldehyde, see U.S. Pat. No. 2,852,563.
Among dimerization processes is the Dimersol.RTM. dimerization process for dimerizing olefins using a nickel coordination complex and an aluminum alkyl as catalyst. The process can convert propylene to hexenes with selectivity in excess of 85%. The hexenes can be converted by oxo reaction to aldehydes and then alcohols, producing heptanols. M. Johnson has studied oxo reaction of 4-methylpen-1-ene, showing migration of the double bond during the reaction, and fairly large production of a 2-substituted aldehyde, 2,4-dimethylpentanal, along with 5 methyl-hexanol as the main product (J. Chem. Soc. 1963, 4859).
Reactions of the type described characteristically produce mixtures of isomeric products. Therefore in the production of plasticizer alcohols, distillations may be employed at an early stage to separate isomeric materials. An alternative is to effect selective reaction of the isomeric materials with resulting effect upon product properties.